Galvanic cell.



H. P. R. L. PURSGKE.

GALVANIG CELL.

APPLICATION FILED JULY 16. 190-1.

91 9 ,457, Patented Apr. 27, 1909.

JQ/ gg' formed.

HEINRICH PAUL RUDOLF LUDWIG PURSCKE, O l HAMBURG, GERMANY.

GALVANIG CELL.

Specification of Letters Patent.

Patented April 27, 1909.

Application filed July 15, 1907. Serial No. 383,937.

To all whom it may concern: r

Be it known that 1, Hammer! PAUL liroonr Lrnwic PimscKE, a subject of the German 'Emperor. residing at Hamburg, (urermany, have invented certain new and useful Improvements in Galvanic Cells, of which the following is a specification.

This invention relates to improvements in galvanic cells containing chlorid of iron. hlorid of iron'is used as a depolarizer in certain galvanic cells, and the use of diaphragnis'or gypsum has been pro osed .for the purpose of preventing the di usion of the chlorid to the negative electrode. diaphragms do not, however, retain their efliciency for any considerable length of time.

The present invention is based on the fact that a gelatinous mass is produced by mixing chlorid ofiron with arabic acid, metarabic acid, or gums such as gum arabic containing acids of the arabin group.

For the purpose of the invention the positive electrode may be produced in the known manner, for example by mixing graphite and manganese peroxid in suitable propor-- .uons and inolstening the mixture with a highly concentrated or more or less dilute solutionof chlorid of iron. An improved method of producing the positive electrode consists in mixing and compressing carbon, manganese peroxid, ferrous hydrate, and chlorid of iron, the purpose of the hydrate in this mixture being to decompose the excess of hydrochloric acid which may be A considerable proportion of chlorid of iron may be used, approximately onethird by-weight of the entire mixture. A rod or cylinder of carbon is embedded in the mixture, and the positive electrode thus formed is placed in a suitable vessel, which may, for example, consist of zinc and be used as tlife; negative electrode. The electrolyte introduced into this vessel may bea solution of chloridof zinc, salammoniac, or magnesium chlorid," or a mixture of these three 'compounds'in solution, but other suitable electrolytes mayalso'be used. In each case the electrolyte is mixed with arabic acid or metarabic acid, for'example by in-, troducing thereinto gum arablc contalnm 1 a considerable proportion of arable aci bone-meal or other absorbent material be,- ing added to the mixture to reduce a pasty mass. The positive electr' e is referably wrapped in canvas or the like be ore being Such.

' thereto of a embedded in the electrolytic mass, the cell being thereupon sealed in the usual manner.

The cell produced in the manner described has on open circuit'an electromotive force of approximately 2 or 2.1 volts, and during the discharge thereof the electromotive force is at all times approximately 0.4 or

0.5 volts higher than that of a cell of similar dimensions containing carbon and peroxid of manganese unmixed with chlorid of iron. In the improved cellthe depolarization is more efiicient than in cells in which the depolarizer is manganese peroxid alone, so that the discharge can' take place with higher current-values. The diffusion of the chlorid of iron to the negative electrode is prevented by the presence of the arabic or metarabic acid, since the passage of a small quantity of the chlorid through the -canvas wrapper of the positive electrode causes a conductive, gelatinous film or layer to be produced betweenthe chlorid and the electrolyte, further difiusion of the chlorid being thus prevented.

The annexed drawing shows an embodi- .ment of the improved cell, Figure 1 being a vertical central section and Fig. 2 a plan view thereof.

a indicates the exterior vessel, It the negative electrode, 6 the positive electrode consisting of the constituents previously described and carried in a casing 0 and through which passes the carbon rod (1.

e is the electrolyte with admixture of gum arabic and f and g the positive and negative terminals respectively.

\Vhat I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. In a galvanic cell, the combination with a. positive electrode and a negative electrode, of a depolarizing mixture containing chlorid of iron, an electrolyte and an admixture thereto of an acid of the arabin group.

2. In a galvanic cell the combination with a positive electrode and a negative electrode,

of iron, an electrolyte, and an admixture gum containing arabic and lnetarabic acids.

'3. In a galvanic cell the combination with a positive electrode and a negative electrode of a depolarizing mixture containing graphite, manganese. peroxid, chlorid of of a depolarizing mixture containing chlorid iron, and ferrous hydrate, an electrolyte and an admixture thereto of an acid of the arabin group.

4. In a galvanic cell the combination with a positive elect-rode and anegative electrode of a depolarizing mixture containing graphite, manganese peroxid, chlorid of iron,iand ferrous hydrate, and electrolyte and an admixture thereto of a gum containing arable and metarablc aclds.

5. In a galvanic cell the cpmbination with a positive electrode and a negative electrode, of a depolarizing mixture containing Vchlorid of iron, an electrolyte, an admixture th.ereto of,an acid of the arabic group and a further admixture to said electrolyte of an absorbent material;

l. 6. In a galvanic cell the combination a de olarizing mixture containing 7 chlorid of iron, an electrolyte, an admixture thereto of a gum containing arabic and metarabic acids and a' further admixture-to said electrolyte of an abserbent material,

with a fpositive electrode and a negative electrode, 0

'2. In a galvanic cell the combination with a i ositive electrode and a negative electrode, 0 a" depolarizing mixture containing graphite, manganese peroxid, chlorid of iron, and ferrous hydrate, anelectrolyte, an

admixture thereto of an acid of thearabin group and a further admixture to said electrolyte ofan absorbent material.

8. Ina galvanic cell the combination with a positive electrode and a negative electrode, of a depolarizing mixture containing graphite, manganese peroxid, chlorid of iron, and ferrous hydrate, an electrolyte, an admixture thereto, of a gum containing arabic and metarabic acids and a further admixture, to said electrolyte of an absorbent material.

In Witness, whereof llhave signed this specification in the presence of two Witk nesses.

HEINRICH PAUL'RUDQLF LUlbWIG PfiRSCKE.

Witnesses: v

Smermnn Srronon, Urn) W. HELLMRICH. 

